Coils of magnet wire are typically wound onto a stator core by way of a winding ram or spindle which is reciprocated through the bore of the stator core along a fixed horizontal axis and oscillated about the horizontal axis adjacent each end of the reciprocal stroke of the winding spindle. Magnet wire is drawn from a source of wire under tension through the winding spindle and through a winding head, which comprises one or more wire-guiding needle tips projecting outwardly from a needle head secured at one end of the winding spindle. As the winding spindle is reciprocated and oscillated, the magnet wire pays out through a wire exit nozzle of each needle tip to form coils of wire around pole pieces on the stator core.
In certain circumstances, a stator manufacturer may desire to wind wires having different diameters onto identically configured stator cores in order to achieve different electrical characteristics from the resulting stator coils. However, in order to wind different sizes of wire onto the stator cores using a single winding machine, it is often necessary to adjust the length of the needle tips, i.e. the distance that the wire exit nozzles thereof are spaced outwardly from the longitudinal axis of the winding spindle, to a proper length for a given wire diameter. Fine wire pays out of a needle tip with a sharp, sometimes ninety degree bend at the wire exit nozzle of the needle tip and thus casts a relatively small arc as it exits the needle, whereas heavy wire pays out of the needle tip at a less severe angle and casts a larger arc. Because it is desirable for the wire exiting the needle tip to follow a path as close as possible to the inner surface of the stator core, a needle tip having a greater length is required for winding fine wire onto a stator in comparison to the needle length required for winding heavier gauge wire onto the same stator core.
The length of a needle tip in a conventional winding head is typically adjusted by removing the needle tip and replacing it with a different needle having an appropriate length, which requires significant down time and attention from an operator. There are known stator winding machines which permit the length of the needle tip to be adjusted, but such machines are intended to be adjusted during coil winding operations in order to obviate the need for coil winding shoes or forms. As a result, adjustment of the needle length is synchronized with the reciprocal and oscillatory motion of the winding spindle, which requires a complex and expensive construction.